July 2014

A Decade of Atmospheric Research in the Tropical Western Pacific

Long-term ARM datasets critical for cloud and solar energy studies.

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Image courtesy of Julia Flaherty, Pacific Northwest National Laboratory

The Atmospheric Radiation Measurement (ARM) Climate Research Facility has three user facility sites in the tropical western Pacific: Manus, Papua New Guinea; Nauru Island, Republic of Nauru; and Darwin, Australia.

The Science

The Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility has collected atmospheric data for more than a decade in the equatorial tropical western Pacific (TWP), an important climatic region. A team of researchers led by DOE’s Pacific Northwest National Laboratory (PNNL) has analyzed the scientific utility of these measurements and provided examples of their value.

The Impact

Strong solar heating, warm sea surface temperatures, and the annual progression of the Intertropical Convergence Zone across the TWP region generate abundant convective systems that profoundly affect global climate and precipitation. To accurately evaluate tropical cloud systems in climate models, long-term measurements of tropical clouds, the environment in which they reside, and their impact on radiation and water budgets are needed.


Because of its remote location, ground-based datasets of cloud, atmosphere, and radiation properties from the TWP region traditionally have come primarily from short-term field experiments. However, these short-term datasets provide only limited statistical and climatological information. To obtain long-term measurements of the surface radiation budget in the tropics and the atmospheric and cloud properties that affect it, ARM established TWP measurement sites in 1996. The PNNL team’s analysis gives examples of the wide range of scientific uses of these unique long-term datasets, including characterization of cloud properties, analysis of cloud radiative forcing, model studies of tropical clouds and processes, and validation of satellite algorithms. The impact of recently installed instrumentation on new opportunities for tropical atmospheric science also is discussed. The study highlights contributions of ARM TWP data to increased knowledge of tropical cloud systems and the tropical surface radiation budget.


Charles Long
Pacific Northwest National Laboratory, P.O. Box 999, MSIN: K4-28, Richland, WA, 99352


This research is supported by the DOE Office of Science Biological and Environmental Research program as part of the ARM and Atmospheric System Research programs.


Long, C., et al. “ARM research in the Equatorial Western Pacific: A decade and counting.” Bull. Amer. Meteoro. Soc. 95 (5), 695–708 (2012). [DOI: 10.1175/BAMS-D-11-00137.]

Highlight Categories

Program: BER, CESD

Performer/Facility: University, DOE Laboratory, SC User Facilities, BER User Facilities, ARM

Last modified: 11/19/2015 9:04:03 AM